Prosthetic heart valves are used to replace damaged or diseased heart valves. In vertebrate animals, the heart is a muscular organ with four pumping chambers: the left and right atria and the left and right ventricles, each provided with its own one-way valve. The natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid and pulmonary valves. Prosthetic heart valves can be used to replace any of these naturally occurring valves, although repair or replacement of the aortic or mitral valves is more common since they reside in the left side of the heart where pressures are the greatest.
A conventional heart valve replacement surgery involves accessing the heart in the patient's thoracic cavity through a longitudinal incision in the chest. For example, a median sternotomy requires cutting through the sternum and forcing the two opposing halves of the rib cage to be spread apart, allowing access to the thoracic cavity and heart within. The patient is then placed on cardiopulmonary bypass which involves stopping the heart to permit access to the internal chambers. Such open heart surgery is particularly invasive and involves a lengthy and difficult recovery period.
Minimally invasive surgical techniques are evolving, where a valve prosthesis can be introduced into a patient using a catheter that is introduced via a small incision that provides access to, for example, a femoral artery or directly to the heart. These implantation techniques have shown promising results in providing treatment options for patients who are poor open surgical candidates. Nevertheless, challenges still remain in such catheter-based delivery of prosthetic valves. Advancing a tubular delivery device through a vessel exerts stress against the vessel walls and is carries the risk of damaging the vessel walls. For example, retrograde delivery of a valve through the femoral artery has been associated with aortofemoral artery injury/rupture, and carries a potential risk of stroke as the delivery involves crossing the aortic arch. Accordingly it is advantageous to design a valve prosthesis delivery system which minimizes damage along the delivery path of device while also minimizing the invasive nature of the implantation procedure.
In one embodiment described herein, a heart valve prosthesis delivery device allows implantation of an aortic valve prosthesis to correct a defective aortic valve. This device introduces the valve prosthesis through an introducer into the left ventricle of the heart (transapical delivery). In another embodiment disclosed here, a valve prosthesis delivery device is designed to take advantage of the relatively large diameter of the arteries and veins leading directly to the heart. This device is designed, for example, for use by a surgeon able to access these arteries and veins percutaneously such that introduction of the delivery device is done relatively close to the heart to take advantage of the larger diameter of the vessels.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.